1. Field of the Invention
The present invention generally relates to car and truck receiver hitches for towing and carrying, and more particularly to eliminating undesirable free-play between a receiver insert and its mated hitch tube.
2. Description of the Prior Art
Receiver style trailer hitches come in a variety of capacities for various applications, and are generally classified as either weight-carrying or weight-distributing. The weight-carrying type of hitch is used for trailer weights up to 5,000 lb. and where the weight and suspension of the tow vehicle can accommodate that load. Weight-distributing hitches are normally used for heavier trailers up to 10,000 lb., and when the weight and suspension of the tow vehicle in relation to the trailer weight requires a redistribution of the weight.
Receiver style hitches typically comprise a receiver tube section that is securely attached to a tow vehicle's frame. A ball-mount shank tongue is slipped into the receiver tube and locked in place with a hitch pin. The trailer can then couple and pivot on the ball-mount shank tongue. The ball-mount shank tongue and its adapter are easy to remove and store, and can even be exchanged with others of other sizes, or that carry the ball at different heights, etc. The receiver tube can also receive utility carriers for bikes, skis, cargo, etc. Plumbers and other craftsmen who routinely work from their trucks also commonly attach tool mounts and work platforms to receiver tubes.
Receiver tubes are ordinarily sized slightly larger than necessary to allow the ball-mount shank tongue to be easily installed or removed. This usually means there is free-play, e.g. about 0.030 inch, between the receiver tube and ball-mount shank tongue even after the lock pin is put in place. Such free-play allows the ball-mount shank tongue to move about in the receiver tube during use, e.g., while towing, turning, starting, or stopping, and from wind.
The loose connection of the ball-mount shank tongue can cause rattling and bumping sounds that Eire annoying and distracting to passengers. Sport utility vehicle and van passengers often sit inside the vehicle and very near the hitch connection, where any receiver hitch noise can be even more pronounced.
Tow and carry receiver adapters are now available that allow a user to both mount a bicycle carrier and tow a trailer. A bicycle carrier is welded to a collar piece that telescopes over a ball-mount shank tongue and is firmly seated. The ball-mount shank tongue is then inserted into the receiver tube, secured with a hitch pin, and the trailer to be towed is coupled to the ball-mount shank tongue's hitch ball. The long twisting arm of the bicycle carrier on the loose ball-mount shank tongue can allow the carrier to wobble quite a bit. Prior art article carriers, tool mounts, and work platforms used with receiver style hitches do not incorporate means for eliminating wobble or instability caused by free-play between ball-mount shank tongue and the receiver tube.
An anti-wobble/anti-rattle device is therefore needed that is compatible with existing ball-mount shank tongues and carrier inserts, and not require modifications to existing equipment. Such a device would preferably, be easily added to receiver hitch style article carriers, tool mounts, and work platforms at the time of manufacture.
U.S. Pat. No. 4,856,686, issued to Larry Workentine, describes an article carrier that can be attached to a ball-mount shank tongue to permit towing and carrying at the same time. However, no provision is disclosed for eliminating undesired free-play between the ball-mount shank tongue insert and a receiver hitch tube.
U.S. Pat. No. 5,593,172, issued to Patrick W. Bristlin, describes a receiver hitch anti-rattle device for ball-mount shank tongues. A disadvantage of this device is that it can loosen during heavy loads when subjected to repetitive towing maneuvers such as turns, starting, stopping, and backing up. A sports carrier would wobble from side to side during a tow and carry situation.
U.S. Pat. No. 4,050,714, issued to Walter H. Epp, describes a trailer hitch attachment that slips over the ball-mount shank tongue before it is inserted into the receiver tube end. After the locking clevis pin is inserted, a pair of adjusting bolts are used to press the ball-mount shank tongue aft in its connection and to load the locking clevis pin. The ball-mount shank tongue can thereby be locked tightly in the receiver tube by adjusting two bolts to eliminate all wobble. Unfortunately, very few standard ball-mount shank tongues have the necessary bosses that the collar plates could bear on, and the design generally is suited for weight-distributing type hitches.
U.S. Pat. No. 5,333,888, issued to Ball, and U.S. Pat. No. 5,224,133, issued to Abbott, et al., describe a sliding wedge type receiver hitch insert, but ball-mount shank tongues and article carriers already in use could not practically be retrofitted to incorporate these mechanisms.
U.S. Pat. No. 5,344,175, issued to Speer describes a mechanism for eliminating movement in trailer hitch receivers. However, it is not sufficiently sturdy for use in heavy towing operations nor could it be practically incorporated into existing ball mounts or article carrier inserts.
U.S. Pat. No. 5,615,904, issued to Van Dusen, et al.; U.S. Pat. No. 5,449,101, issued to Van Dusen; and U.S. Pat. No. 5,181,822, issued to Alisop, et al., all describe a screw means of pressing or pulling one sidewall of a sports carrier insert tightly against one sidewall of a receiver hitch tube to reduce undesired movement between ball-mount shank tongue and the receiver hitch tube. Unfortunately, such embodiments require the use of a modified hitch pin.
U.S. Pat. No. 5,664,717, issued to Brian K. Joder, and U.S. Pat. No. 5,529,231, issued to Ronald J. Burgess, each describe a side clamping piece on the receiver mounting insert that can be tightened against one side of the rim of the receiver tube after installing the locking clevis pin. Such a device is not expected to be entirely effective in eliminating wobble when heavy loading and twisting forces are applied to the hitch assembly, e.g., during trailer towing.